I. Field of the Invention
The present invention relates to sunscreens. More particularly, the present invention relates to sunscreens that protect the scalp and hair from the damaging effects of sunlight.
II. Description of the Prior Art
Sunscreen compositions are applied to the skin to protect the skin from the sun's ultraviolet rays that can lead to erythema, a reddening of the skin also known as sunburn. Sunlight or ultraviolet radiation in the UV-B range has a wavelength of 290 nm to 320 nm and is known to be the primary cause of sunburn. While, ultraviolet rays at a wavelength of 320 nm to 400 nm, known as UV-A radiation, produces tanning of the skin. However, in the process of doing so, the UV-A rays can damage or harm the skin.
Besides the immediate malady of sunburn, excessive sunlight exposure can lead to skin disorders. For instance, prolonged and constant exposure to the sun may lead to actinic keratoses and carcinomas. Another long-term effect is premature aging of the skin. This condition is characterized by skin that is wrinkled, cracked and has lost its elasticity.
In general, sunscreen compositions are oil and water emulsions. In this system, the UV-absorbing compounds are typically incorporated into the oil phase.
Sunscreens may also include physical or inorganic metal oxides that block the sun's rays. Titanium dioxide and zinc oxide are commonly used for this purpose.
As stated above, sunscreens are typically formulated with the goal of inhibiting skin damage from the sun's rays. The sunscreen composition filters or blocks the harmful UV-A and UV-B rays that can damage and harm the skin. It is believed that sunscreen agents accomplish this by absorbing the UV-A and/or UV-B rays.
However, the skin is not the only area that can be harmed by the sun's rays. Hair can also suffer damage from excessive exposure to the sun. For example, the hair cuticle can be damaged, which leads to a split end. In addition, the hair can become brittle and dry and also experience color fading.
Consumers consider many factors when purchasing a sunscreen product. One of the most important considerations is the sun protection factor (SPF). This determines the amount of protection that the sunscreen composition provides over a given period of time. There are many to choose from and selection will be based upon the consumer's needs. The consumer also gives consideration to the substantivity of the product, that is how durable is the product after applying it. This effects how often the composition will need to be applied when the consumer is out in the sun. A third consideration is product feel and how well the product spreads. Typically, consumers want a product that feels smooth and silky. Another factor is the shelf life of the product, which is determined by the chemical and physical stability of the sunscreen composition. In addition, product form will also play a part since there is a variety of choices such as lotions, gels, creams, sprays, and aerosols that are available.
However, if the consumer is searching for a sunscreen product that protects the scalp and hair from ultraviolet irradiation, he or she will be forced to use a sunscreen product that is meant to be applied on the skin. The result is that the scalp may be protected, but the hair may not be. As such, there is a need to provide the consumer with a sunscreen product that is specifically formulated to provide protection to both the scalp and hair from the damaging effects of the sun that can lead to color fade, dryness, and cutical separation. Furthermore, the product provides the additional benefit of imparting grooming and styling benefits.
U.S. Pat. No. 5,681,554 claims a cosmetic composition for treating hair that contains a hydrolyzed protein comprising anionic and cationic amino acids, a divalent cationic compound, a vitamin compound, and a cosmetic carrier.
U.S. Pat. No. 5,616,331 claims a topically applicable sunscreen/cosmetic composition for the photoprotection of human skin and/or hair against the damaging effects of UV-A and/or UV-B irradiation. The composition is an ultrafine oil-in-water emulsion of homogeneously and finely dispersed particulates of an inorganic nanopigment of a metal oxide, such as titanium dioxide. The average particle size of the globules in the oily phase is in the range from 100 nm to 1,000 nm.
U.S. Pat. No. 5,601,811 discloses cinnamido amine cationic quaternary salts that have UV-absorbing properties. These compounds are soluble in water and when used in formulations, typically will improve skin feel by reducing the greasy, oily feel that one normally finds.